Easy opening container wall

ABSTRACT

An easy opening container wall comprising a container wall of sheet material having a line of weakness therein defining a tear portion at least partially removable from the container wall. Removal of the tear portion provides a relatively sharp edge along the tear portion. A guard is provided along the periphery of the tear portion to protect the consumer from injury. The guard is interrupted adjacent the location at which the line of score is initially ruptured to facilitate such initial rupture. The outer periphery of the guard and the score line are configured and positioned relative to each other to minimize interference by the guard during the opening operation.

United States Patent 1 1 Schubert et al.

1 Sept. 24, 1974 EASY OPENING CONTAINER WALL [76] Inventors: James R.Schubert, 4243 Merrimac Ave., Dayton, Ohio 45405; Omar L. Brown, 148Napoleon Dr., Dayton,

Ohio 45429 22 Filed: Feb. 28, 1973 [21] App]. No.: 336,404

Related US. Application Data [63] Continuation-impart of Ser. No.238,187, March 27,

[56] References Cited UNITED STATES PATENTS Baugh et a1 220/54, Holk,Jr. 220/54 Primary ExaminerGe0rge T. Hall [57] ABSTRACT An easy openingcontainer wall comprising a container wall of sheet material having aline of weakness therein defining a tear portion at least partiallyremovable from the container wall. Removal of the tear portion providesa relatively sharp edge along the tear portion. A guard is providedalong the periphery of the tear portion to protect the consumer frominjury. The guard is interrupted adjacent the location at which the lineof score is initially ruptured to facilitate such initial rupture. Theouter periphery of the guard and the score line are configured andpositioned relative to each other to minimize interference by the guardduring the opening operation.

17 Claims, 12 Drawing Figures PATENIED sum 2 m 7 3.837. 524

, w a RN 7 III/II M 8 Q; v .m Mm m wg k [III/II PATENIEDSEPZMQH 3337.524SIEH 30$ 7 NWN EASY OPENING CONTAINER WALL CROSS REFERENCE TO RELATEDAPPLICATION This application is a continuation-in-part of applicationSer. No. 238,187 filed Mar. 27, 1972, for COM- BINED CAN AND END WITHMEANS FOR PRO- TECTING AGAINST SEVERED SCORE.

BACKGROUND OF THE INVENTION As is well known, when an easy openingcontainer is opened, a tear portion or panel is torn from the containerto form an opening. The tearing of the sheet ma terial leaves arelatively sharp edge on the removed panel and also leaves a relativelysharp edge on the rim of the opening. These sharp edges are potentialsources of danger to the consumer particularly if the container orremoved panel is carelessly handled.

This problem is particularly acute in the so-called full panel pulloutin which the removed panel covers a major area of the can end. Thesefull panel pullout ends are often used on a food product such aspudding, some of which may adhere to the inner or non-public side of thepanel. When this occurs, the consumer may lick the inner surface of theremoved panel and by so doing may cut his tongue. This of course is onlyone example of how one of the sharp edges on the panel can produceinjury.

In our earlier copending application, this problem is solved by aprotector or guard on the tear portion which extends along the peripheryof the tear portion. The guard provides a relatively dull surfaceadjacent the sharp edge which shields the user from the sharp edge.

In one form, the guard includes multiple layers of sheet material formedintegrally with the tear portion. Although the guard very adequatelysolves the injury problem, it introduces two additional problems. First,the guard inhibits the initiation of severance of the sheet materialalong the line of weakness. Specifically, easy opening container wallsof this type are typically opened by depressing a peripheral segment ofthe tear portion inwardly. The guard, which may be in the form of arelatively stiff guard bead on the inner side of the tear portion,resists inward movement of the peripheral segment. Therefore, theinitial pop is more difficult to obtain.

Following the initial pop, a paddle section of the tear portion is bentinwardly, usually about a bend zone, to rupture a segment of the sheetmaterial along the line of weakness. This inward bending of the paddlesection is typically brought about by pivotal movement of the openingtab.

Following such pivotal movement of the tab, the user pulls outwardly onthe tab to pull out the panel from the container wall. The guard,however, has an edge which lies radially outwardly of the line ofweakness. This edge tends to hang up during the initial pull on the tabso that the initial portion of the pulling phase of the openingoperation is made more difficult.

SUMMARY OF THE INVENTION The present invention facilitates the initialseverance or pop of the sheet material at the line of weakness byinterrupting the guard at the peripheral segment of tear portion whichis depressed inwardly. Interruption of the guard could be a simpleabsence of the guard at the peripheral segment. However, this would meana loss of protection at the peripheral segment. Accordingly, a betterform of interruption is an appropriate discontinuity of the guardwithout completely eliminating it.

In one preferred form of the invention, the guard includes a guard beadlocated axially inwardly of the line of weakness. With thisconstruction, the guard is interrupted at the peripheral segment byspacing the guard bead axially inwardly from the peripheral segment tothereby allow the peripheral segment to be forced inwardly to initiaterupture of the sheet material without substantial interference from theguard bead. Another advantage of this construction is that when theperipheral segment is forced inwardly, it is deformed into substantialcontact with the guard bead. Accordingly, the guard bead, once the tearportion is removed, is fully effective, even at the peripheral segment,to protect the user against injury.

The present invention also facilitates the initial pull phase of thetear portion removal operation. The guard has an edge on the inner ornonpublic side of the container wall which extends generally along theline of weakness. The edge of the guard lies radially outwardly of theline of weakness along a major portion of the line of weakness tothereby provide maximum protection against injury from the sharp edge.However, the edge lies slightly radially inwardly adjacent the portionsof the line of weakness which are ruptured by the initial pull on thetab. As the edge lies radially inwardly of these portions of the line ofweakness, it cannot increase the resistance to the initial pull of thetab. Al-

though the edge may lie slightly radially outwardly of a major portionof the line of weakness, it has been found that this does not create anysignificant resistance to the pulling phase of the removal operationafter the initial pull is accomplished The present invention alsoprovides a novel and advantageous method of making a double fold insheet material. This method can be used to particular advantage inconstructing a preferred form of the easy opening container wall of thisinvention.

According to the method of this invention, a piece of sheet material isprovided with the sheet material having first and second axially offsetradial sections integrally joined by a generally axial wall. The secondradial section has an expansion rib formed integrally therewith adjacentthe axial wall.

Next axially directed compressive forces are applied to the expansionrib to completely flatten the rib. Flattening of the rib results in theapplication of a radial outward force to the adjacent end of the axialwall. The effect of collapsing the expansion rib is to incline the axialwall in a known direction so that when axial compressive forces areapplied to the two radial sections a double fold will be provided. Asthis double fold or pair of reverse bends is of the type which can beused to form a guard-for the easy opening container wall of thisinvention, this method is particularly adapted for use in making thepreferred form of the easy opening container wall.

Another feature of the method of this invention is the manner in whichthe guard bead is caused to be spaced from the peripheral segment of thetear portion which is first ruptured by the tab. This can beadvantageously accomplished by providing a space into which the guardcan move during the work operation which results in the formation of theguard.

The invention can best be understood by reference to the followingdescription taken in connection with the accompanying illustrativedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of an easyopening container having a protector to protect the user against injuryfrom the sharp edge of the tear portion.

FIG. 2 is an enlarged fragmentary sectional view taken generally alongline 22 of FIG. 1.

FIG. 3 is a fragmentary sectional view of the container with the panelremoved.

FIGS. 4 and 5 are enlarged fragmentary sectional views taken generallyalong lines 4-4 and 55, respectively, of FIG. 1.

FIG. 6 is a schematic plan view of the container wall with the tabremoved showing the relationship between the peripheral edge of theguard and the score line.

FIG. 7 is a top plan view of a can end blank.

FIG. 8 is a fragmentary sectional view taken along line 8- 8 of FIG. 7.

FIG. 9 is a sectional view taken on an axial plane and illustrating thetooling for forming a dimple and for coining the connecting wall.

FIG. 10 is a sectional view taken on an axial plane showing the toolingfor converting the dimple into a hollow rivet and for formation of therib.

FIG. 11 is a sectional view taken on an axial plane and illustrating thetooling for initiating axial collapse of the rib and axial compressionof the radial sections.

FIG. 12 is an enlarged fragmentary sectional view taken on an axialplane illustrating the axial compression of the container wall to formtwo reverse bend sections.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1-5 illustrate an easyopening container 11 in the form of an easy opening can. The container11 includes a generally cylindrical peripheral wall 13 of sheetmaterial, the upper end of which is closed by an easy opening containeror end wall 15 which is attached to the upper end of the peripheral wallby interlocking flanges 17 and 19. The lower end or bottom of theperipheral wall 13 can be closed in any conventional manner such as byan end wall intregral therewith or by an end wall which is attached tothe lower end of the peripheral wall in a conventional manner.

The peripheral wall 13 may be of conventional construction except for anannular rib 21 which projects radially inwardly closely adjacent andbeneath the wall 15.

The easy opening container wall 15 is constructed of sheet material suchas aluminum or an aluminum alloy. The easy opening container wall 15 hasa line weakness in the form of a score line 23 which defines arelatively large panel or tear portion 25 which can be removed from thecontainer 11. The panel 25 covers a major portion of the area of thecontainer wall 15 and has an inner or non-public surface 26. Theconfiguration of the score line 23 is described in connection with FIGS.4-6. An annular coined region 26a of reduced thickness extends along thescore line 23.

A tab 27 is attached to the panel 25 in any suitable manner such as by ahollow rivet 29. Although the tab 27 could be of various constructions,in the embodiment illustrated, it is of the type disclosed in commonassignees copending application Ser. No. 64,291. The tab 27 isintegrally constructed from a single piece of sheet metal and generallyincludes a tab body or lever 31 and an attaching portion or ear 33 whichis connected to the tab body 31 by a connecting wall 35. The rivet 29projects through the attaching ear 33 to attach the tab 27 to the panel25. The tab body 31 has a lifting end 37 and a rupturing flange 39 atopposite ends thereof.

The tab body 31 has an outer reinforcing curl 43 which extendssubstantially completely around the tab body except for the rupturingflange 39. Adjacent the connecting wall 35, the curl 43 has legs 45 and47 connected by a bend portion 49 which the latter being engageable withthe connecting wall 35. The bend portion 49 is round and acts to supportthe connecting wall during manipulation of the tab.

An outer or marginal region of the panel 25 has the sheet materialthereof bent to form an outwardly opening reverse bend portion 51 and aninwardly opening reverse bend portion 53. The bend portion 53 has asmooth dull surface or outer peripheral edge 55 which lies adjacent thescore line 23. As shown in FIG. 2, the reverse bends 51 and 53 arejoined to the score line 23 and to the panel 25, respectively. Thereverse bends 51 and 53 are interconnected by a connecting leg 57 whichforms an intermediate layer of the marginal portion of the panel 25. Asshown in FIG. 2, the reverse bend 53 lies axially inwardly of the scoreline 23.

More specifically, a marginal region of the panel 25 is bent to form anupper layer 56 of sheet material, a

lower layer 56a of sheet material and the intermediate layer orconnecting wall 57. All of the layers 56, 56a, and 57 are annular andextend continuously around the marginal portion of the panel 25. Thelayers 56, 56a and 57 and the bends 51 and 53 form a guard bead. At alllocations along the score line 23 except for the region adjacent therupturing flange 39 (FIG. 2) the layers 56, 56a and 57 are substantiallyparallel, and the layers 56 and 56a are flattened against theintermediate layer 57, as shown in FIG. 4. With this construction, theintermediate layer 57 abuts the upper layer 56 over substantially thefull length of the intermediate layer.

However, at the region of the score line 23 adjacent the rupturingflange 39, the intermediate layer 57 is not bent into tight supportingengagement with the upper layer 56. Rather, as shown in FIG. 2, theintermediate layer 57 projects radially outwardly and axially inwardlyin extending from the bend 51 to the bend 53. With this construction,the intermediate layer 56 is not backed up or supported immediatelyaxially inwardly of the score line 23. This facilitates the initiationof severance of the sheet material along the score line 23, i.e., theinitial pop.

When the lifting end 37 of the tab 27 is raised, the connecting wall 35of the tab readily bends to allow the tab body 31 to pivot relative tothe attaching ear 33. This forces the rupturing flange 39 against thesheet material at a region of the score line 23 and tends to force aperipheral segment of the layer 56 so engaged by the rupturing flange 39axially inwardly. If the intermediate layer 57 were in tight engagementwith the inner face of the layer 56, it would support the latter,

and therefore resist the inwardly directed force applied by therupturing flange 39. However, with this invention, the layers 56a and 57are spaced axially at the region axially inwardly of the rupturingflange 39 so that the layer 56 is unsupported in this region.Accordingly, the region of the score line 23 engaged by the rupturingflange 39 is ruptured with about the same ease as though the guard beadwere not provided.

Upon continued pivotal movement of the tab body 31, the tearing of thesheet material along the score line 23 continues to thereby rupture asegment of the line of weakness. Such pivotal movement of th tab body 31also bends a paddle section 58 of the panel inwardly into the container11 to form an opening 58a (FIG. 3). The inward pressure applied to thelayer 56 by the flange 39 may tend to bend the layer 56 into engagementwith the layer 57 as shown in phantom lines in FIG. 2. The tab 57 isthen pulled outwardly to rupture the remainder of the sheet materialalong the score line 23 thereby removing the panel 25 from the container11.

The rupture of the sheet material forms a relatively sharp edge 59 on thpanel 25 as shown in dashed lines in FIG. 2 and a relatively sharp edge60 on the container (FIG. 3). The dull surface or edge 55 preferablylies closely adjacent the sharpedge 59 to form a shield or partialsheath therefor. In addition, the edge of the panel 25 is thick becauseit is defined by the three layers of sheet material 56, 56a and 57.These two factors combine to make it extremely difficult to be injuredby the sharp edge 59.

The rib 21 on the peripheral wall 13 preferably projects radiallyinwardly so that the edge 55 of the paddel section 58 just clears therib 21 as the paddle section is bent inwardly of the container 11. Asshown in FIG. 3, the rib 21 projects radially inwardly through alocation which is in substantial alignment with the sharp edge 60. Thus,the rib 21 serves as a guard to make cutting contact with the sharp edge60 much more difficult.

To facilitate the initial pull of the tab 27, the present inventionprovides certain relationships between the edge 55 and the score line23. With reference to FIG. 6, pivotal movement of the tab body 31 bendsthe paddle section 58 inwardly about a bend zone or line 58b. Althoughthe bend line 58b is shown as a straight line in FIGS. 1 and 6,obviously it may have other configurations. This results in tearing of asegment of the score line 23 lying intermediate points 580 and 58d whichdefine the ends of such segment and the ends of the bend line 58b.

The present invention orients the edge 55 and the score line 23 in sucha way as to achieve maximum protection from injury and to facilitate theinitial pull of the tab 27. To obtain maximum protection, the edge 55preferably lies slightly radially outwardly of the score line 23 so thatit can better protect the user against injury from the sharp edge 59. Onthe other hand, it has been found that if the edge 55 lies radiallyoutwardly of the score line 23 adjacent the points 580 and 58d, the edge55 tends to hang up on the rim of the opening 58a (FIG. 3). Accordingly,this invention provides for locating the edge 55 radially outwardly ofthe score line 23 along substantially all of the score line except forthe regions of the score line adjacent the points 58c and 58d.

A preferred way of configuring and positioning the score line 23 and theedge 55 is shown in FIG. 6. The edge 55 is circular in plan. The scoreline 23 contains a circular portion 23a which is concentric with theedge 55. The circular portion 23a is a major portion of the score line23 and, in the form shown in FIG. 6, extends for approximately 270 ofthe score line. Obviously, the circular portion 23 may extend througharcs other than 270.

The score line 23 also includes a pair of arcuate sections 23b and 23cwhich, in the embodiment illustrated, extend through the same number ofdegrees and have radii of identical lengths. The radii of the arcs 23band 230 are smaller than the radius of the circular portion 23a, and forthis reason each of the arcs 23b and 230 forms a hump on the score line23. The circular portion 23a terminates at reference lines XX and YY.The arcs 23b and 230 intersect at reference line ZZ, which is a radialline along which the rupturing flange 39 engages the score line 23, andterminate at lines YY and XX, respectively.

With this construction, the edge 55 lies slightly radially outwardly ofthe circular portion 23a as shown in FIGS. 4 and 6. At and adjacent thepoints 58c and 58d,- the edge 55 lies slightly radially inwardly of thescore line as shown in FIG. 5. At and adjacent the rupturing flange 39(reference line Z-Z in FIG. 6) the edge 55 lies radially outwardly ofthe score line 23 as shown in FIGS. 2 and 6. The location of the points580 and 58d may vary depending upon the manner in which the tab body 31is manipulated. Accordingly, it is preferred to have the edge 55 lieradially inwardly of the score line 23 along regions of sufficientlength to accommodate all reasonable variations in locations of thepoints 580 and 58d.

In FIG. 6, the humps formed by the arcs 23b and 23c have beenexaggerated for clarity. In actual practice, the score line 23 mayappear to be substantially circular in plan. In the embodimentillustrated, the arcs 23a, 23b and 230 have centers C1, C2, and C3,respectively.

With the construction shown diagrammatically in FIG. 6, the edge 55 liesradially inwardly of the score line 23 and hence from the edge 60 (FIG.3) at the points 580 and 58d. Accordingly, the edge 55 cannot hinderremoval of the tear portion 25. The edge cannot even where locatedradially inwardly of the score line 23 is sufficiently close to thesharp edge 59 to afford substantial protection. In addition, tongueinjuries of the type described hereinabove are less likely to be causedon the paddle section 58 because this portion is bent and not as easy tolick.

FIGS. 7-12 illustrate a preferred method of constructing the easyopening container wall 15 shown in FIGS. 1-6. FIGS. 7 and 8 show a canend blank 61. The blank 61 includes a peripheral attaching flange 63, anaxial wall 65 and a pair of radial walls or sections 67 and 69 which areaxially offset and interconnected by a generally axial or connectingwall 71. In the embodiment illustrated, the section 67 and the wall 71are annular, and the section 69 is circular. The blank 61 may be formedinto this configuration with any suitable tooling.

FIG. 9 shows a first work operation in which a dimple 73 is formed andin which the connecting wall 71 is coined to elongate the same. In FIG.9, the connecting wall 71 is squeezed between a lower coining die 75 andan upper coining die 77 with the compressive force being sufficient tocause thinning and consequent generally axial elongation of theconnecting wall 71. The elongation of the connecting wall 71 facilitatesformation of the reverse bends 51 and 53. Specifically, the dies 75 and77 have coining surfaces 79 and 81, respectively, which coin the sheetmaterial between reference lines AA and B-B. The lower coining die 75also has horizontal supporting surfaces 83 and 85 for supporting theradial section 67 and an annular region 87 which extends between theconnecting wall 71 and the dimple 73. The tooling provides spaces 88 and88a to accommodate the elongation of the connecting wall 71.

The dimple 73 is formed by a punch 89 and a cooperating die 91. Thepunch 89 engages the sheet material of the section 69 and offsets a zoneof the same into a die cavity 93. Ultimately the offset sheet materialis engaged between the cooperating surfaces of the punch 89 and the die91 to coin the sloping wall of the dimple. The coined regions aregenerally those portions of the dimple 73 which are shown in FIG. 9 asbeing compressively engaged. A dimple making process which involvesstretching and coining of the sheet material is disclosed in commonassignees U.S. Pat. No. 3,638,597. The annular region 87 is not coinedduring the work operation illustrated in FIG. 9.

In the work operation shown in FIG. 10, the dimple 73 is converted intoa hollow rivet 95 and the connecting wall 71 is converted into a shorterconnecting wall or axial wall 97 and an annular expansion rib 99 whichlies between the wall 97 and the rivet 95. The wall 97 extendssubstantially axially whereas the connecting wall 71 (FIG. 9) isinclined or sloped relative to the axis of the blank 61. The annularexpansion rib 99 is closely adjacent the wall 97.

The dimple 73 is converted into the rivet 95 by a rivet punch 101 and arivet die 103. An outer annular region of the dimple 73 is collapsed andflattened between working faces 105 and 107 of the punch 101 and the die103, respectively. The punch 101 has a head 109 which is within therivet 95 to assist the formation thereof, and the rivet 95 is in a diecavity 111.

The expansion rib 99 is formed by stretching and deformation of thesheet material of the connecting wall 71 by a punch 113 and a die 115.The punch 113 has a head 117 which engages the sheet material and forcesthe same into a die cavity 119.

The wall 97 is formed from the upper'regions of the connecting wall 71.This is accomplished by the punch 113, the die and a tool 121. Inaddition, the die 115 cooperates with the tool 121 to bend the sheetmaterial at the juncture of the section 67 and the wall 97 so that thewall 97 extends in a substantially axial direction.

In the work operation shown in FIG. 11, the score line 23 is formed andan axial compressive force is applied to the expansion rib 99 by a pairof compression tools 125 and 127 to completely flatten the expansionrib. The scoring operation can advantageously be carried out by ascoring die 129 and by a tool 131 which supports the section 67. Aspring 130 urges the die 129 and the tool 127 in opposite directions. Inaddition, a punch is partially inserted into the rivet 95.

The tool 127 and the die 129 are advanced relative to the tools 125 and131. The tool 127 strikes the upper end of the expansion rib 99 toinitiate axial collapse and radial expansion thereof. Radial expansionof the expansion rib 99 moves the lower end of the axial wall 97radially outwardly with the wall 97 pivoting about regions 132. Thiscreates a generally Z-shaped cross section with the wall 97 extendingboth axially and radially. In addition, as the scoring tool 129 isrelatively advanced, it applies an axial compressive force to the radialsections 67 and 69 with the result that the wall 97 becomes moreinclined relative to the axis of the blank 61 in the manner shown inFIG. 7. The expansion rib 99 is completely collapsed in the workoperation of FIG. 11.

During the operation shown in FIG. 11, the sheet material adjacent theultimately formed score line 23 is confined by the tool 131 and thescoring die 129. As the die 129 and the tool 131 relatively advance, thesheet material between the die 129 and the tool 131 is compressivelyengaged to hold the section 67 in position and to form the score line23. At the end of the stroke the sheet material radially outwardly ofthe score line23 is coined by a coining face 132a, and this furthertends to hold the section 67 in positin during the last bit of radialexpansion of the expansion rib in the operation of FIG. 11. Ordinarily,the material radially inwardly of a point X will be thinner than thematerial radially outwardly of the score line 23 as a result of thecoining operation of FIG. 9, and consequently the face 132a will notordinarily coin the material radially inwardly of the score line.

By confining and compressively engaging the sheet material adjacent andalong the score line 23 to prevent movement thereof, stresses of thetype which might create tiny cracks or openings in the sheet materialalong the score line are less likely to occur. In addition, slightcoining adjacent the score line 23 is believed beneficial to thecharacteristics of the sheet material along the score line.

FIG. 12 illustrates the next work operation in which the radial sections67 and 69 are moved toward each other with consequent collapse of thewall 97 to form reverse bend sections 51 and 53 substantially as shownin FIG. 2. During the work operation of FIG. 12, the blank 61 isretained between tools or workholders 137 and 139, and the punch 141 isreceived within the rivet.

A compression tool 143 is moved upwardly and cooperates with the tool139 to at least partially collapse the wall 97 (FIG. 11) to thereby formthe reverse bends 51 and 53. Specifically, the compression tool 143 hasan annular working face 147 which is continuous and planar except for aperipheral segment of the tool 143 at which a radial shoulder 149 and anaxial shoulder 151 cooperate to define a recess 153. The recess 153 isformed at the periphery of the tool 143 and extends circumferentiallyfor a very short distance.

The recess 153 increases the spacing between the tools 139 and 143 overwhat it would be without the recess. Accordingly, the sheet material isnot compressed as much by the tools 139 and 143 at the recess 153 as itis where the recess does not exist.

SPecifically, the tools 139 and 143 squeeze and completely collapse thewall 97 to form the configuration shown in FIG. 4 at all locations whichdo not confront the recess 153. This squeezing action of the tools 139and 143 converts the regions 132 (FIG. 11) into the bends 51 and 53,respectively, and the wall 97 (FIG. 11) into the intermediate layer 57as shown in our copending application referenced hereinabove.

At the recess 153, the greater spacing between the tools 139 and 143makes it possible for the layers 56, 56a, and 57 not to be foldedtightly against each other. At the beginning of the work operation ofFIG. 12, the layer 56 is supported from above by a flat annular workingface 156 of the tool 139, and the layer 56a is unsupported from below.Accordingly, the relative advance of the tools 139 and 143 forces theunsupported layer 56a into the recess until the bend 53 engages theshoulder 149. This prevents the intermediate layer 57 from being bent uptight against the upper layer 56. This leaves a space 155 between thelayers 56 and 57 along the circumferential length of the recess 153 asshown in FIG. 12. Thus, the circumferential dimension of the recess 153should be selected in accordance with the desired circumferentialdimension of the cross section shown in FIG. 12, Le, the circumferentialdimension of the interruption of the guard bead. The tool 143 alsocooperates with a pressure pad 157.

Some ofthe material of the connection wall 71 (FIG.-

8) is used to form the reverse bends 51 and 53. Because the connectingwall 71 has been thinned, the reverse bends 51 and 53 are more easilyformed and are less likely to have cracks.

Following the work operation of FIG. 12, the tab 27 (FIGS. 1 and 2) canbe attached to the blank 61 by heading of the rivet 95 to therebyconvert the latter into the rivet 29 (FIGS. 1 and 2). Thereafter, theresulting easy opening container wall can be attached to the container11 as shown in FIG. 2.

Although the method shown in FIGS. 7-l2 is particularly adapted formaking an easy opening container wall of the type shown in FIG. 2, itmay be used in other instances where it is desired to form a double foldor double reverse bend sections.

Although exemplary embodiments of the invention have been shown anddescribed, many changes, modifications and substitutions may be made byone having ordinary skill in the art wihtout necessarily departing fromthe spirit and scope of this invention.

We claim: 1. An easy opening container wall comprising: a container wallof sheet material; a line of weakness in the container wall defining atear portion at least partially removable therefrom;

first means attached to said tear portion for initiating rupture of thesheet material by an inwardly directed force and for tearing the sheetmaterial generally along the line of weakness to at least partiallyremove the tear portion from the container wall, said tearing of sheetmaterial providing a relatively sharp edge on the tear portion, theinitiation of rupture of the sheet material occurring at a preselectedregion along the line of weakness;

second means on the tear portion and extending along a peripheral regionthereof for protecting the user against injury from the sharp edge whenthe tear portion is at least partially removed from the container wall;and

said second means being interrupted adjacent said preselected region ofthe line of weakness sufficiently to substantially prevent said secondmeans from hindering the initiation of rupture of the sheet material inresponse to said inwardly directed force.

2. An easy opening container wall as defined in claim 1 wherein saidfirst means includes a tab at least a portion of which is pivotable torupture the sheet material at said preselected region and along asegment of the line of weakness, said second means lying radiallyinwardly of said line of weakness at the ends of said segment.

3. An easy opening container wall comprising:

a container wall of sheet material;

a line of weakness in the container wall defining a rupturable web; saidrupturable web defining a tear portion at least partially removabletherefrom;

means attached to said tear portion for initiating rupture of therupturable web at a preselected region thereof by an inwardly directedforce and for tearing the rupturable web to at least partially removethe tear portion from the container wall, said tearing of the 'sheetmaterial providing a relatively sharp edge on the tear portion;

a guard on the inner side of said tear portion extending along theperiphery of the tear portion to protect the user against injury fromthe sharp edge; and

said guard being spaced inwardly in a generally axial direction from therupturable web at least adjacent a portion of said preselected regiontofacilitate the initiation of rupture of the rupturable web at saidpreselected region by said inwardly directed force.

4. An easy opening container wall as defined in claim 3 wherein saidguard includes multiple layers of sheet material of the tear portion.

5. An easy opening container wall as defined in claim 3 wherein saidguard includes a guard bead.

6. An easy opening container wall comprising:

a container wall of sheet material;

a line of weakness in the container wall defining a tear portion atleast partially removable therefrom;

means attached to said tear portion for tearing the sheet materialgenerally along said line of weakness to at least partially remove thetear portion from the container wall, said means initiating rupture ofthe line of weakness by forcing a peripheral segment of the tear portioninwardly;

said tear portion including a panel portion having and a marginal regionsubstantially circumscribing said panel section; reverse bend sectionjoined to said panel section and opening generally radially inwardly,

the marginal region of said tear portionhaving a cross sectionalconfiguration which includes a first reverse bend section openinggenerally radially outwardly, a second generally radially inwardly, anda leg section joining said bend sections;

said second reverse bend section being in a radial position closelyadjacent the line of weakness to shield the user against injury from thesharp edge;

said second reverse bend section and at least a portion of said legsection being spaced generally axially inwardly from at least a portionof said peripheral segment to allow said peripheral segment to be forcedinwardly to initiate rupture of the line of weakness without substantialinterference form the bend sections and said leg section.

7. An easy opening container wall as defined in claim 6 wherein saidtearing of the sheet material provides a relatively sharp edge on thetear portion, said bend sections and said leg section at least partiallydefine a protector for protecting the user against said sharp edge, andsaid initiation of rupture deforms said peripheral segment inwardly intosubstantial contact with said leg section whereby the protector can moreefficiently protect the user against injury from the portion of saidsharp edge of the peripheral segment.

8. An easy opening container wall comprising: a container wall of sheetmaterial having an inner side; a line of weakness in the container walldefining a tear portion at least partially removable therefrom;

first means attached to said tear portion for tearing the sheet materialgenerally along said line of weakness to at least partially remove thetear portion from the container wall, said tearing of the sheet materialproviding a relatively sharp edge on the tear portion;

said first means including means for forcing a paddle section of thetear portion inwardly to rupture the sheet material along a segment ofthe line of weakness;

second means on said tear portion for protecting the user against injuryfrom the sharp edge;

said second means including an outer peripheral edge on the inner sideof said container wall extending generally along the line of weakness;and

said edge lying radially inwardly of the line of weakness adjacent theends of said segment and radially outwardly of the line of weaknessalong a major portion of the line of weakness.

9. An easy opening container wall as defined in claim 8 wherein saidedge is circular in plan and said line of weakness is noncircular.

10. An easy opening container wall as defined in claim 9 wherein saidmajor portion of the line of weakness forms a part of a circle which issubstantially concentric with the circular edge.

11. An easy opening container wall as defined in claim 10 wherein theportion of said edge which lies radially inwardly of the line ofweakness includes first and second arcs, each of said arcs forming aportion of a circle and being nonconcentric with each other and withsaid major portion of the line of weakness.

12. An easy opening container wall as defined in claim 8 wherein saidsecond means is interrupted along at least a portion of said segment.

13. An easy opening container wall as defined in claim 8 wherein saidsecond means includes a guard bead, said edge being on said guard head.

14. An easy opening container wall as defined in claim 13 wherein saidguard bead has a cross sectional configuration which includes a firstreverse bend section opening generally radially outwardly, a secondreverse bend section joined to said panel section and opening generallyradially inwardly, and a leg section joining said bend sections, saidedge being a peripheral surface of the second reverse bend section.

15. An easy opening container wall comprising:

a container wall of sheet material;

means forming a line of weakness in the container wall defining a tearportion that is completely removable from said container wall;

means attached to said tear portion for rupturing the sheet material byforcing a paddle section of the tear portion inwardly to rupture thesheet material along a segment of the line of weakness;

means integral with said tear portion for protecting the user againstinjury from the sharp edge formed after severance thereof;

said-integral means being of generally circular shape in plan view, and

said line of weakness being concentric with respect to a portion of saidintegral means and including a portion in the region of said paddlewhich is not concentric with said integral means.

16. An easy opening container wall as set forth in claim 15 whereinintegral means includes a rounded edge defining, in the region ofconcentricity with said line of weakness, a diameter in plan viewsomewhat greater than that of the circle formed by said line ofweakness.

17. An easy opening container wall as set forth in claim 16 wherein saidrounded edge 5 located vertically below the plane of the line ofweakness whereby upon removal of the tear portion the rounded edgeextends beyond the sharp edge in the portion thereof concentric with thesharp edge.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,837,524 Dated Sept. 24, 1974 Inventor(s) James R. Schubert and Omar L.Brown It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

Column 10, line 44, after "panel" delete "portion having" and insertsection-;

Column 10, line 46, after "section; delete remainder of line;

Column 10, delete lines 47 and 48;

Column 10, line 52, after "second" insert reverse bend section joined tosaid panel section and opening-;

Column 10, line 57, change "an" to -and.

Colunm 12, line 40, after "edge" change "s" to is-.

Assignee: Ermal C. Fraze, Dayton, Ohio Signed and Scaled thistwenty-seventh D3) of April 1976 [SEAL] A lies I:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (mnmissium'r uj'lalentsand Trademarks

1. An easy opening container wall comprising: a container wall of sheetmaterial; a line of weakness in the container wall defining a tearportion at least partially removable therefrom; first means attached tosaid tear portion for initiating rupture of the sheet material by aninwardly directed force and for tearing the sheet material generallyalong the line of weakness to at least partially remove the tear portionfrom the container wall, said tearing of sheet material providing arelatively sharp edge on the tear portion, the initiation of rupture ofthe sheet material occurring at a preselected region along the line ofweakness; second means on the tear portion and extending along aperipheral region thereof for protecting the user against injury fromthe sharp edge when the tear portion is at least partially removed fromthe container wall; and said second means being interrupted adjacentsaid preselected region of the line of weakness sufficiently tosubstantially prevent said second means from hindering the initiation ofrupture of the sheet material in response to said inwardly directedforce.
 2. An easy opening container wall as defined in claim 1 whereinsaid first means includes a tab at least a portion of which is pivotableto rupture tHe sheet material at said preselected region and along asegment of the line of weakness, said second means lying radiallyinwardly of said line of weakness at the ends of said segment.
 3. Aneasy opening container wall comprising: a container wall of sheetmaterial; a line of weakness in the container wall defining a rupturableweb; said rupturable web defining a tear portion at least partiallyremovable therefrom; means attached to said tear portion for initiatingrupture of the rupturable web at a preselected region thereof by aninwardly directed force and for tearing the rupturable web to at leastpartially remove the tear portion from the container wall, said tearingof the sheet material providing a relatively sharp edge on the tearportion; a guard on the inner side of said tear portion extending alongthe periphery of the tear portion to protect the user against injuryfrom the sharp edge; and said guard being spaced inwardly in a generallyaxial direction from the rupturable web at least adjacent a portion ofsaid preselected region to facilitate the initiation of rupture of therupturable web at said preselected region by said inwardly directedforce.
 4. An easy opening container wall as defined in claim 3 whereinsaid guard includes multiple layers of sheet material of the tearportion.
 5. An easy opening container wall as defined in claim 3 whereinsaid guard includes a guard bead.
 6. An easy opening container wallcomprising: a container wall of sheet material; a line of weakness inthe container wall defining a tear portion at least partially removabletherefrom; means attached to said tear portion for tearing the sheetmaterial generally along said line of weakness to at least partiallyremove the tear portion from the container wall, said means initiatingrupture of the line of weakness by forcing a peripheral segment of thetear portion inwardly; said tear portion including a panel portionhaving and a marginal region substantially circumscribing said panelsection; reverse bend section joined to said panel section and openinggenerally radially inwardly, the marginal region of said tearportionhaving a cross sectional configuration which includes a firstreverse bend section opening generally radially outwardly, a secondgenerally radially inwardly, and a leg section joining said bendsections; said second reverse bend section being in a radial positionclosely adjacent the line of weakness to shield the user against injuryfrom the sharp edge; an said second reverse bend section and at least aportion of said leg section being spaced generally axially inwardly fromat least a portion of said peripheral segment to allow said peripheralsegment to be forced inwardly to initiate rupture of the line ofweakness without substantial interference form the bend sections andsaid leg section.
 7. An easy opening container wall as defined in claim6 wherein said tearing of the sheet material provides a relatively sharpedge on the tear portion, said bend sections and said leg section atleast partially define a protector for protecting the user against saidsharp edge, and said initiation of rupture deforms said peripheralsegment inwardly into substantial contact with said leg section wherebythe protector can more efficiently protect the user against injury fromthe portion of said sharp edge of the peripheral segment.
 8. An easyopening container wall comprising: a container wall of sheet materialhaving an inner side; a line of weakness in the container wall defininga tear portion at least partially removable therefrom; first meansattached to said tear portion for tearing the sheet material generallyalong said line of weakness to at least partially remove the tearportion from the container wall, said tearing of the sheet materialproviding a relatively sharp edge on the tear portion; said first meansincluding means for forcing a paddle section of the teaR portioninwardly to rupture the sheet material along a segment of the line ofweakness; second means on said tear portion for protecting the useragainst injury from the sharp edge; said second means including an outerperipheral edge on the inner side of said container wall extendinggenerally along the line of weakness; and said edge lying radiallyinwardly of the line of weakness adjacent the ends of said segment andradially outwardly of the line of weakness along a major portion of theline of weakness.
 9. An easy opening container wall as defined in claim8 wherein said edge is circular in plan and said line of weakness isnoncircular.
 10. An easy opening container wall as defined in claim 9wherein said major portion of the line of weakness forms a part of acircle which is substantially concentric with the circular edge.
 11. Aneasy opening container wall as defined in claim 10 wherein the portionof said edge which lies radially inwardly of the line of weaknessincludes first and second arcs, each of said arcs forming a portion of acircle and being nonconcentric with each other and with said majorportion of the line of weakness.
 12. An easy opening container wall asdefined in claim 8 wherein said second means is interrupted along atleast a portion of said segment.
 13. An easy opening container wall asdefined in claim 8 wherein said second means includes a guard bead, saidedge being on said guard bead.
 14. An easy opening container wall asdefined in claim 13 wherein said guard bead has a cross sectionalconfiguration which includes a first reverse bend section openinggenerally radially outwardly, a second reverse bend section joined tosaid panel section and opening generally radially inwardly, and a legsection joining said bend sections, said edge being a peripheral surfaceof the second reverse bend section.
 15. An easy opening container wallcomprising: a container wall of sheet material; means forming a line ofweakness in the container wall defining a tear portion that iscompletely removable from said container wall; means attached to saidtear portion for rupturing the sheet material by forcing a paddlesection of the tear portion inwardly to rupture the sheet material alonga segment of the line of weakness; means integral with said tear portionfor protecting the user against injury from the sharp edge formed afterseverance thereof; said integral means being of generally circular shapein plan view, and said line of weakness being concentric with respect toa portion of said integral means and including a portion in the regionof said paddle which is not concentric with said integral means.
 16. Aneasy opening container wall as set forth in claim 15 wherein integralmeans includes a rounded edge defining, in the region of concentricitywith said line of weakness, a diameter in plan view somewhat greaterthan that of the circle formed by said line of weakness.
 17. An easyopening container wall as set forth in claim 16 wherein said roundededge s located vertically below the plane of the line of weaknesswhereby upon removal of the tear portion the rounded edge extends beyondthe sharp edge in the portion thereof concentric with the sharp edge.